A flash memory is a non-volatile memory device. The flash memory uses flash memory chips as the storage medium and data stored in the memory chips would not be lost after power-off. Therefore, flash memories are widely used as external or internal storages. A flash memory device, which uses flash memory chips as the storage medium, is also known as a solid state disk (SSD) or a solid state drive (SSD).
A SSD generally includes multiple flash memory chips. Each flash memory chip includes several blocks. Generally, when storing data received from the outside, the SSD may concurrently write the data to multiple blocks to improve data processing efficiency. When performing garbage collection processing, the SSD needs to obtain valid data from multiple blocks and move the valid data to a free block or blocks. The operations may cause write amplification.